A closure frame is an assembly of frame components arranged into a preferred shape. These frame components may be formed from solid wood or plastic hollow structure produced by extrusion. An example of such closure frame would be a doorframe which usually includes jambs and upper transverse member enclosing the sides and top of a doorway. The doorframe supports a door that is useful in closing of the doorway. Another example of a closure frame would be a window frame which encloses sides, top and bottom of a window usually covered with a glass pane.
Closure frames made of solid wood may have relatively high shock and sound absorption abilities but their fire resistance capability would be comparatively low. With in mind a more economical substitute for reasonable mechanical strength and fire resistance properties, plastic doorframe is made available. The component forming the doorframe are usually hollow structure defined or bounded by a single layer plastic skin that is created with a fixed cross-sectional profile by way of extrusion. The presence of a hollow interior may compromise the mechanical strength of the overall frame. Wooden blocks may be inserted into the hollow interior for supporting the installation of locks or other accessories. Such wooden block should offer some enhancement of mechanical strength but other properties such as fire resistance capability demand improvement at reasonable costs.
The invention seeks to eliminate or at least to mitigate such shortcomings for enhanced performance by providing a new or otherwise improved closure frame component.